PENKO

Manual

13 14 15 16

-SUP +SUP

19,2-31,2V

P1 P2 P3 P4

ZERO-C ZERO-F SPAN-C SPAN-F

ZERO/SPAN ADJUST

SGM 424

STRAIN GAUGE TO 4-20mA CONVERTER

LOADCELL 4-20mA

+E +S -E -S +IN -IN Sh CAL Sh -I +I

1 2 3 4 5 6 7 8 9 10 11 12

Strain gauge converter type SGM424

INDUSTRIAL INSTRUMENTATION

S424-MAN

SGM424

Power supply

24Vdc

(-20% to +30%)

GND +

13 14 15 16

13 14 15 16

-SUP +SUP

19,2-31,2V

P1 P2 P3 P4

ZERO-C ZERO-F SPAN-C SPAN-F

ZERO/SPAN ADJUST

SGM 424

STRAIN GAUGE TO 4-20mA CONVERTER

LOADCELL 4-20mA

+E +S -E -S +IN -IN Sh CAL Sh -I +I

1 2 3 4 5 6 7 8 9 10 11 12

1 2 3 4 5 6 7 8 9 10 11 12

+ Excitation

+ Sense

+Signal

- Signal

- Sense

- Excitation

Strain gauge sensor

ADJUSTMENT OF THE STRAIN GAUGE CONVERTER

TYPE SGM420-2.

1.

First mount the loadcell(s) mechanical without any friction under the weigher. The loadcell cable has to be connected to the

12-pole connector:

+ loadcell supply (+excitation) at clamp-1 +E.

- loadcell supply (-excitation) at clamp-3 -E.

+ sense at clamp-2 +S.

+ sense at clamp-4 -S.

+ signal (input) at clamp-5 +IN.

- signal (input) at clamp-6 -IN.

Screen of the cable (shield) at clamp Sh.

2 . Connect the power supply 24Vdc (-20% to

+30%) to the 4-pole connector.

LOWPASS FILTER

DIP3 & 4 = OFF = 2,5Hz (default)

DIP3 & 4 = ON = 25Hz

Default is all dipswitches off

Z-COARSE Z-FINE S-COARSE S-FINE

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3. Analog filter setting. Choose with dipswitch 3 & 4 the analog low-pass filter.

At 2,5Hz the disturbance is the least but the analog output will react slowly. The converter is faster at 25Hz but the surrounding such as vibrations has more influence.

For weigh applications we advise to set the dipswitch to 2,5Hz.

Set the dipswitch as shown at the picture above.

BB

BB

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SGM424

P1: ZERO ADJUST COARSE

P2: ZERO ADJUST FINE

P3: SPAN ADJUST COARSE

P4: SPAN ADJUST FINE

Adjusting the current output:

13 14 15 16

-SUP +SUP

19,2-31,2V

P1 P2 P3 P4

ZERO-C ZERO-F SPAN-C SPAN-F

ZERO/SPAN ADJUST

SGM 424

STRAIN GAUGE TO 4-20mA CONVERTER

LOADCELL 4-20mA

+E +S -E -S +IN -IN Sh CAL Sh -I +I

1 2 3 4 5 6 7 8 9 10 11 12

4.

Measure with a current-meter at clamp +I an -I the current output.

5.

With an unloaded weigher the current must be adjusted to

4mA. First use potentiometer-1 for COARSE and then potentiometer-2 for the FINE-adjusting.

6.

Place the maximum load at the weigher. Adjust the mAsignal to 20mA with potentiometer-3 for COARSE and then potentiometer-4 for FINE-adjusting.

It’s also possible to load the weigher with a smaller load ( at least 10%). Because the load cell signal is linear to the load, the output signal must also adjusted to 10% => 5.6mA.

7.

Repeat step 5 and 6 when necessary.

1 2 3 4 5 6 7 8 9 10 12

+

R-Load

750 Ohm max

I-Load 4-20mA

Z-COARSE Z-FINE S-COARSE S-FINE

BB

BB

BB

BB

SPAN SELECTION

(USE ONLY AT CALIBRATION PROBLEMS)

Dip1 & 2 = OFF = Gain = 800x (default)

Dip1 = ON = Gain = 1200x

Dip1 & 2 = ON = Gain = 2000x

Sometimes the needed amplification is too small.

In this case there’s a possibility to increase the gain.

Set the dip switch 1 & 2 to amplify more. First start with dip1 ON and when this still is too small also close dip 2.

Note!!! don’t use the dip switch when not necessary

This is important because the amplifier can seize up. A larger gain also will increase temperature effects. Always try to check the whole gain

(from zero to max weight).

19,2-31,2V ZERO/SPAN ADJUST

SGM 424

STRAIN GAUGE TO 4-20mA CONVERTER

SGM424

The CAL function:

The function of CAL is to get a reference value out of the

SGM424. Afterwards the weigher can checked to see if the signal hasn’t been passed away. After the converter has been calibrated a contact can be connected to CALL (clamp 8 &9). Close the contact and measure the reference-value. Notice this referencevalue for the gain.

This function is mostly meant for automatic systems to control if 1 of the loadcells is defect.

Specifications:

Power supply:

Bridge excitation:

Number of loadcells:

Signal input range:

Safe input voltage:

Output:

Input Impedance:

Linearity:

Temperature effects:

Analog filter

Tarra range:

Span range:

Calibration input:

Consumption:

Dimensions:

Weight:

Case:

24 Vdc (19,2V - 31,2V max.)

10 Vdc.

1-4 loadcells of 350 Ohm or 1-8 loadcells of 1kOhm.

0-20 mV.

0-18 V.

4-20 mA .

10 Gohm.

0.02%, 12 bits.

on zero 0.005%/deg.C, on span 0.0025%/deg.C of FS.( gain=800)

2.5Hz or 25Hz. (2.5Hz standard, 25Hz selectable inside).

up to 75% (2mV/V loadcells).

10% to 100% (2mV/V loadcells).

potential free contact.

3,5 Watt (4 loadcells of 350 Ohm).

70 x 85 x 60 mm.

200g.

DIN case acc. IEC 529/DIN VDE 0470-1,ABS plastic.

Galvanic isolation from the power supply optional.

other input ranges or filter frequencies on request.